Turbine rotor



July 8, 1924.,

A.. S. ANDERSON TURBINE ROTOR Filed Sept. 20, 1922 Inx/efit or 1 AlbertS." Anderson,

W M f His Attorne Patented July 8, 1924. p

' L NET E STATES 15%,787 PATENT GFFECE.

ALBERT s. ANDERSON, OF'SCHENECTADY, NEW yo-3K, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF- NEW YORK.

TURBINE ROTOR.

Application filed September 20, 1922. Serial No. 539,454.

T all whom it may concern:

Be it known that I, ALBERT S. ANDERSON,

a citizen of the United States, residing in Schenectady, in the countyof Schenectady, State of New York, have invented certain new and usefulImprovements in Turbine Rotors, of which the followingis aspecification. 1

The present invention relates to turbine rotors and specifically to theso-called filling blocks for closing the slot or opening through whichthe bases of the buckets or blades are introduced into thebase-receiving grooves in the rotor body.

The object of the invention is to provide a simple filling blocktogether with means for securely anchoring it in place.

For a consideration of What I believe to be novel and my invention,attention is directed to the accompanying specification and the claimsappended thereto.

In the drawing, which is illustrative of.

my invention, Fig. 1 is a partial section of a bucket wheel; Fig. 2 is apartial side view 01 such a wheel, and Fig. 3 is a perspective View of afiller block.

4 indicates the rim portion of a wheel body or rotor, 5 the buckets and6 the bucket bases. The rim is provided with two annular grooves whichare of inverted T- shaped section, the overhanging walls or shoulders 7of the grooves being indicated by dotted lines. On each bucket base aretwo projections arranged side by side each being ofinverted T-shapedsection and of such size as to fill the grooves and engage the shoulders7 The central member 8 of the rim which is between the grooves is T-shaped in cross section as shown by thedotted lines, and has overhangingwalls or shoulders 9. At one or more points in the circumference of therim, usually two at diametrically opposite points, the overhanging wallsor shoulders are cut away to their full depth, as indicated in fulllines, to form filling slots. Each of these cut-away portions or slotsis of a length slightly greater than the thickness of a bucket base sothat the latter can be slipped into place by a radial movement, afterwhich each bucket base which conforms in shape to the inverted T-shapedgrooves is forced around in said grooves to its final position. Thisoperation is continued until the rotor is fully bucketed.

In order to prevent the buckets from working loose it is necessary toprovide filling blocks for the aforesaid filling slots. The block mustof course conform in shape and size to the walls of the filling slot andalso to the space which is left between adj acent buckets, and requirescareful fitting, for even the slightest space may cause one or morebuckets to workloose. These filling blocks of necessity are ofconsiderable weight and when the rotor is revolving at its designedspeed are, due to centrifugal force, tending to tear loose fromtheirfastenings. It is sometimes necessary to repair bucket wheels, asfor example, to remove damaged buckets and insert new ones, and thiswithout removing the wheel from its shaft. This is not a simple matterin any event but where the buckets are very long, 26 in the presentcase, and where a number of wheels are strung on the shaft side by sideand close together the problem becomes a serious one. It will be evidentthat it is no easy matter to reach over or between such long buckets andget at the filling blocks,

and also that the anchoring means for the blocks must be of such acharacter that they can be removed and replaced-withoutinjury to thewheel body. On account of the nearness of the adjacent wheels it followsthat the said means must be short axially since otherwise they could notbe removed and replaced. I ,7

One of the filling blocks 10 is shown in Fig. 3 and is in the form of aninverted U vhavingparallel legs or sides 11 and a connecting piece 12 atthe top. The block as a whole is slightly tapered from the top to thebottom as shown in Fig. 2 so as. to compensate for the difference indiameter of the bottom of the" wheel grooves and that of the outer endsof the bucket bases. The legs straddle the central member 8 of the wheelwhich is located between the bucket receiving grooves. The connectingpiece at the top of the block is slightly longer than the space betweenthe sides of the bucket grooves so as to rest on the peripheral surfaceof the wheel. Each leg is also provided with an end notch or slot 13. Todecrease the weight of the block so as to reduce the centrifugal force,holes 14 are provided therein. In the sides of the wheel rim and inaxial alignment with each filler block are dove-tail grooves 15, Fig. 2,ar-

ranged to receive the short axially extending anchoring devices 16. Eachdevice has beveled or inclined sides and a square inner end which fitsnugly into the notch 13. Owing to the arrangement of these devices orkeys the filling block, when the wheel is in service, exerts a shearingeffect thereon and this is taken care of by making the devices ofsuitable cross-section. The outer end of each device follows the contourof the Wheel rim but does not extend quite to the surface. The purposeof this is to permit the metal of the rim and adjacent the device to becalked or peaned over, as indicated by the dotted lines 17, 2,.toprevent said device from accidentally working out when the wheel is inuse.

It should be noted that the filling block is slightly tapered from topto bottom from which it follows that when the block is driven home itwill exert sidewise pressure on the bucket bases thereby completelyfilling the space. It should also be noted that the devices or wedges 16by reason of their shape and location exert an inward or downwardpressure on said blocks and thus hold them securely in place.

Assuming that it is desired to repair a wheel by inserting one or morenew buckets, the calked or peaned over portions 17 which are nearest tothe injured bucket are forced back, after which said devices may beremoved. The next step is to pull out the slightly tapered fillingblock, and this may be done by inserting tools in the dovetail slots 15with the inner ends of the tools in the notches-13 and exerting upwardpressure on the block. After this the buckets can be forced back to thefilling slot one after the other and removed. After the damaged bucketis removed the rebucketing will be carried on in the usual manner andthe filling slot closed as before described.

In accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof,but I desire to haveit understood that the apparatus shown is onlyillustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is

1. A turbine rotor comprising a body having a bucket receiving groovewith overhanging walls, said walls being cut away to form a fillingslot, buckets in said groove, a filling block which is located in saidslot, said block being provided with transverse notches in its endwalls, and axially extending means which are carried by the body andengage said notches to hold the block in place.

2. A turbine rotor comprising a body having a bucket-receiving groovewith overhanging walls, said walls being cut away to form a fillingslot, buckets in said groove, a filling block which is located in saidslot and which is slightlytapered from the top.

toward, the bottom, said block being provided with transverse notches inits end walls, and axially extending wedges which are carried by thebody and enter said notches to hold the-block in place.

3. A turbine rotor comprising a body having a bucket-receiving groovewith overhanging walls, said walls being cut away to form a fillingslot, buckets in said groove, a filling block which is located in saidslot and which is slightly tapered from the top toward the bottom, saidblock being provided with transverse notches in its end walls, axiallyextending wedges which are carried by the body and enter said notches tohold the block in place, and means for holding the wedges against axialdisplacement.

4. A turbine rotor comprising a body hav ing a central T-shaped memberand grooves of inverted T-shaped section on opposite sides thereof, theoverhanging walls of the member and grooves being cut away to form afilling slot, buckets having bases which occupy the grooves and areinserted into them through the filling slot, a U-shaped filling block,located in the filling slot and provided with transverse notches inits-end walls, and axially-extending means carried by the body whichengage said notches to anchor the block on opposite ends.

In witness whereof, I have hereunto set my hand this 19th day ofSeptember, 1922.

ALBERT S. ANDERSON.

